Steel bit for rock drills



x Oct. 20,1925- A. TERRILL STEEL. BIT FOR ROCK DRILLS Filed June 30. 1923 flLHERT 7723mm...

Patented Oct. 20, 1925.

I UNITED STATES 1,557,143 PATENT OFFICE.

ALBERT TERRILI, OF HAILEYBURY, ONTARIO, CANADA.

STEEL BIT FOR ROCK mums;

Application filed June 30, 1923. Serial No. 648,760.

To all whom it may concern Be it known that I, ALBERT TERRLLL, a subject ofthe King of Great Britain, and resident of the town of I-Iaileybury, in the ,Province. of Ontario and Dominion of readily detached for the purpose of sharpen" ing or otherwise.

Further objects of the invention are to provide a steel bit for a rock drill of this.

character that will give more efiicient and longer service than any heretofore or at present in use. 7

With the foregoing'and other objects in view the invention consists essentially in the arrangement and construction of parts described in the present specification and illustrated by the accompanying'drawings that form a part of same.

Referring now to the drawings in'which likecharacters of reference indicate corresponding parts in each figure:

Figure 1 is a perspective view of an embodiment of my invention.

' Figure 2 is aside elevation of the whole.

Figure 3 is a plan view of the under side of the device as a whole.'

Figure 4 is a side elevationof the upper portlon.

Figure 5 is'an under side view of the under side of the upper portion. I

Figure 6 is a perspective detail of the lower bit of one of the bit members.

' Figure 7 is a similar view of the other bit member.

In the drawings, A represents the device as a 'whole, comprising a stem portion 10 formed with a transversely extending slot 11, provided with a tongue 12' The topof the stem on each side ofthis slot is pro-' vided with tongue. members 13, bevelled at 14. I,

15 is a bit member formed with a groove 16, adapted to fit into the slotted'stem 10, and to engage with the tongue 12 thereon. This bit member is provided with a slot 17,111 which is formed a tongue 18, adaptwith the tongue members on the top of the stem.

19 is a second bit member adapted to fit.

into the slot 17 and to lock with the tongue 18 therein and extending at right angles to the first mentioned bit member 15 and forming in combination therewith a substantially star-shaped cutter as shown in Figure 1. It should'be noted that the bevelling of the tongue 18 enables the second bit engagin therewith to automatically lock, thus holding it securely inposition and at the same time forming the means for locking the first bit in position .on the stem. I The tongue of the first bit may also be bevelled, if necessary, to lock with the stem.

20 is a central aperture extending through the two bits and through the stem, designed to provide a central opening to allow water.

to flow therethrough.

Relative to the bar 19, the groove is .beveled and islarger at one end than the other to engage with a complementary constructed tongue in the bit 15 so that the bit 19 is thus designed to tightly engage from one side inwardly with the' bit 15. In other words, by means of a beveled groove and tongue connection through'these bits being formed larger at one end and gradually smaller at the other, not only is a downwardly disconnecting movement of the bit 19 prevented but also horizontal movement. From the foregoing it wilhbe seen that I have invented a compact, eflicient and practical steel bit for rock drill, with interchange-able bits whereby a singlestem is adapted to be used with any number of bits, and whereby bits by being frequently renewed and sharpened are always in condition to give the most efficient and the longest service.

As many changes could be" made in the above construction and many apparent-1y widely different embodiments of my inven' tion within the scope of the claims, constructed without departing from the spirit or scope thereof, it is intended that all mated, when the bit is in position, to register bit for the stem formed with a groove to engage with the tongued slot in the stem, a.

tongued slot in said bit, a' second bit hav- ,ing a groove adapted to slidably engage with the tongued slot in the first bit where by the bits are securely retained in position on the stem.

2. In a device of the character described, a steel bit for a rock drill comprising a slotted stem, formed with tongues extending at righttangles to one another, one of said tongues being transversely 0n the slotted portion and the other tongue on the unslotted portion, a bit .formed with a groove at its lower end adapted to engage 3. In a device of the character described, the combination with a stem having a tongued slot therein andtongues on each side of the slot, of a bit adapted to fit into said slot and to engage'with the tongue therein and at right anglesthereto, a tongued slot in said bit,.and 'a second bit adapted to slidably engage with the tongued slot in the first bit and at right angles thereto, whereby a star-shaped cutter is formed.

4. In a tool of the character described, the combination with a stem formed with a glurality of tongues, of a bit adaptedto ovetail into said stem, and a second bit, means formed in said bit adapted to slidably engage With the first bit and the tongued stem, whereby the bits are retained.

in position onethe stem.

In witness whereofI have hereunto set my hand.

. ALBERT TERRILL. 

